Answer:
[tex]\angle FCB[/tex]
Step-by-step explanation:
Supplementary angles are angles that sum to [tex]180^{\circ}[/tex]. In this case, [tex]\angle FCB[/tex] is supplementary to [tex]\angle DCF[/tex] since they add up to the angle of a straight line which is [tex]180^{\circ}[/tex].
Hope this helps :)
